From Fish Hooks Wiki
Albert Glass gets Dropsy, a disease which Principal Stickler calls "chickenpox for fish". Milo fakes having that same disease, getting special treatment and attention. Milo panics when he learns he will be sent away so he doesn't infect everyone. Bea and Oscar try to get Milo to confess. Meanwhile, Bea helps Albert Glass get better by giving him tuna fish casserole, which Milo wants.
Milo Gets a Ninja
Fishing for Compliments: The Albert Glass Story